See the link below for a thread from the mini rose forums about saving a mini rose gift. First, you'll want to let the rose sit outside in the shade for a few days. You want it to get used to the outdoors. Be sure to keep it watered. Those pots that the minis are in are usually fairly small. Then follow the instructions for separating the roses. There are usually 3-4 in a pot. Once they are separated then you can go ahead and plant them or pot them. You can fertilize them once they've bloomed but not before. Too much fertilizer will hurt the roots.

I hope that helps. You'll have to see if they get blackspot or other diseases in your climate. They're usually good here. Next spring you'll have to cut off the dead canes, but that's easy, and then it will regrow.